The invention pertains to the field of the petrochemical industry, mainly to methods and systems for fractionation of oil derivatives in vacuum rectification columns.
An operational process of a system for distilling liquid products is known, which includes feeding of a stock product into a vacuum rectification column, fractionation of the stock product in the said column into a vapor phase and a liquid fraction and evacuation of the vapor phase by a steam jet apparatus (see U.S. Pat. No. 2,680,709, cl. 202-204, 1954).
The same U.S. patent introduces a system for distilling liquid products, which has a vacuum rectification column with pipelines for bleeding of the vapor phase and liquid fraction, and a steam jet apparatus.
This system implementing the above described operational process provides the vacuum distillation of liquid products, oil derivatives, as a rule. However, during operation the system produces a mixture of oil derivatives and water, which is formed during evacuation of the vapor phase from the column. Discharge of the mixture into drainage results in environmental pollution whereas purification of such waste water is very expensive.
The starting point for the method of operation of a system for liquid product distillation, which includes in feeding of a stock product into a vacuum rectification column, fractionation of the stock product in the said column into a gas-vapor phase and at least one liquid fraction, evacuation of the gas-vapor phase by a liquid-gas ejector, has been disclosed in RU patent 2048156, cl. B 01 D 3/10, 1995. According to this patent a motive liquid is delivered from a separator into a nozzle of the ejector. Flowing from the nozzle, the liquid entrains the gas-vapor phase. Then the motive liquid mixes with the gas-vapor phase and compression of the gas-vapor component of the mixture takes place.
The same RU patent describes a system for liquid product distillation, having a vacuum rectification column with pipelines for bleeding of gas-vapor phase and at least one liquid fraction, and a vacuum-producing device composed of a liquid-gas ejector, a separator and a pump.